Process and apparatus for manufacturing ground-wood pulp



I 1,633 733 June 28, 1927. F. K. FISH'JR PROCESS AND APPARATUS FORMANUFACTURING GROUND WOOD PULP Filed Ju1yl4. 1925 ATTORNEYS.

liatented 28,1927.

UNITED STATES PATENT OFFICE.

FREDERICK K. FISH, m, 01' m M61800, CAIJJ'OBYIA.

P300388 AND RPmTU 'B I03 IAC'IUBING GBOUND-WOOD PULP.

Application fled m 14, ms, mm In. ,5, a in Canada 1mm 21, ms.

This invention-relates toa-process and apparatus for manufacturingground wood 11] p Iii the manufacture of paper pulp, I have found thatunusual results can be obtained by the employmentof liquor previouslyused in digesting and cooking the'pul'p, the resinous and solvent consttuents with which this li uor. is charged, apparently-serving to attaiikand-otherwiseact on like constituents and on the fiber material'togreatly disintegrate the fibers and im rovetheir condition for pulppurpose. lthout attempting a full explanation as to how or why reuse ofthe digesting liquor brings about such favorable results, I may saywithout contradiction that the fact remainsthat there is an action.brought about, whether chemical or physical, lfcannot' say,which has ensabled me to'lgreatl greduce the cost of the] manufacture of, vp'u p:from mater als which it has been .Ithough be wholly unfitted for pulppu' josesf These resu tshaveflledime .toutilize this broad principle. 7in, the manufacture of, groundwood-pul'p', and it is therefore theobject of thepresent invention to rovide: an a paratus and a process fortreating the woo -beforeau'd. at thev time of grinding tofaoilitategseparation of the individual fibers and saturate the fiberswith solvents or extractives, which materially enhances the value of theproduct and greatly expedites its manufacture. v I

In grinding 'pulpwood', it is the usual practice to moisten'the stoneand the log at-or about the grinding surfaces, and great in; preventingtoo care must be exerc much of the water xing 1 with the pulp stock.According-tomyfkinvention, I. introduce liquor tot 'e-"logs vinthe formof a spray, care bein takento regulate the spray to a suificientdeg'reefso that the logs wi l absorb only the necessary and desired suppallz ofmoisture, and: then provide 'means to t e up any excess; liquor,andsubsequently circulate itiniisp'ray form tothe logs.

' Another o bject 'of'this inventionis to rovide aprocess-for:'treatingjthe logs Iw ile and previous" to grinding-with aliquor charged with dissolved solvent extractives from wood to soften,saturate,-and penetrate, the fibers to "insure of longer and strongerfibers in'the final product, hence a better and-stronger product.

Another objectof the invention is the provision of means for introducingliquor charged with dissolved solvent extractives from wood into theindividual fibers at the point of se aration from the log, so that theyThe invention also comprehends improvements in the construction "andarrangement of parts, and steps in the process, which will behereinafter described and particularly pointed out in the claims.

In the accompanying drawing, I: have shown diagrammatically an apparatusfor carryin out the invention.

1 .--'n icates a magazine, suitably located andl-su 'fported above arotating stone 2, the lattero '3 represents I a" tank locatedconveniently above the'stone and magazine, and it isprovidedwitha'"valved steam inlet .4, and a valved liquor inlet 4. 7 isa pipe communicating with the bottomofthe tank 3, and extendingtherefrom are branch pipes 7", having valves 8, and discharging into themagazine at varlous levels. A pipe 9 cominunicates with the bottom oftank 3,, and it is provided with a valve 10 and communicates with theexhaust side of a pump 11, the opposite side of which is connected witha pipe 12 which leads to the bottom of the magazine in close proximityto the periphery of the grinding stone 2, as shown at 12. This polnt ofcommunication 12 of pipe 12 with the magazine is so located that excessliquor from the sprays-and what may be squeezed from the pulp in therotation of the stone and the logs is withdrawn from the magazine beforeit passes out of the magazine and becomes mixed with the pump anddischar ed therewith into the grinder pit. While have shown but one suchconnection, it is obvious that I may withdraw this excess liquor atseveral points to accomplish this end.

A valved steam inlet pipe 13 is provided at one or more points at thelower portion of the magazine above the pulp forming zone, toadmitsufiicient steam to maintain and increase the temperature'of theliquid.

course beingthe grinding medium.

In the pulp industry, it is well recognized of pulp as wood wellsaturated.

that dry or partially dried wood does not grind as readily or produce asgood grinding the wood, it is necessary to limit the amount of waterorliquor supplied to the grinder, and ultimately mixed with the groundwood from which the pulp stock is ultimatel formed, otherwise the pulpis of low gra e and frequently, when too wet,

is useless.

In the process of grinding heretofore known to me, it has not beenpossible to obtain the required saturation of the wood in the grinder,and at the same time maintain the required suppl of water in thesubsequently-formed pu p. According to my invention, I am not only ableto regulate the liquor .supply to saturate the logs for convenientgrinding, but in addition, I am able to regulate the moisture content ofthe pulp stock, and thus meet the objection heretofore pointed out.

In the operation of m invention, wood, in the form of logs, is fe intothe magazine and supported on the stone which forms a bottom. One ormore of the valves 8 are opened, depending on the height of logs in themagazine, and water previously heated b steam passed throu h pipe 4, andpreferably primarily charged with solvent extractives and stored in tank3, under pressure, is s rayed through pipes 7 to-the wood.

he spray or sprays injected into the magazine has considerable force,with the result that the liquor thoroughly penetrates and saturates thewood, and the solvent extractives contained in the liquor attack theconstituents of the wood and partially dissolve and extract same. Thesepartially melted and dissolved constituents, in the transit of the logsthrough the magazine, are largely released by the everincreasingly-enriched liquor which is continuously circulated over andbetween the logs in the magazine.

The temperature of the spray of liquor on the logs while-in the magazinemay be regulated by passing steam through pipe 13, which with the heatin the liquor and the continued movement of the logs causes vapor andgases formed by the dissolved constituents in the logs to rise in themagazine and around the logs. These vapors condense and the liquor. ofcondensation accumulates in the bottom of the magazine, but as stated,care must be taken to avoid too much of the liquor in the grinding zone.The vapors, consequently the liquor, become surcha-rged with theextractives and constituents liberated from the logs. Hence, theconstituents in the logs are attacked and acted upon by likeconstituents which better prepares the wood for the grinding action, andleads to a definite and defined separation of the fibers,

' features most important and essential in the making of ground pulp.The heat from ad ii? iii the liquor is largely conserved in themagazine, which assists largely in assisting the sprayed liquorpenetrating the logs.

The liquor accumulates at the bottom of the magazine and is drawnthrough ipe 12', by 11 to the tank 3 and is t ere reheate is liquor maybe continuously or periodically umped, but in any event, it iscontinuous y surcharged with the extractives and constituents liberatedin the magazine, so that in'the continued operation of the pump, thespray, heat, and the contained wood constituents in the liquor softens,dissolves, and removes, portions of the encrusting material'of the woodfiber and thus prepares the wood for efiicient economical grindin 7Steam may be admitted to the ma azine from time to time, through thevalve pipe 13, which will discharge into the magazine at a point orpoints best ada ted to secure the required temperature in t e charge,but

care must be taken not to raise the temperature excessively by admittingtoo much steam.

In the usual processes of grinding wood, the vapors which ordinarilypass upwardly in the magazine, owing to the heat generated at the stone,have a tendency to cause discoloration of the resulting pulp, but thisis overcome in my rocess owing to the uantity of liquor use which liquorabsorbs t e steam and vapors and adapts them for advantageous use in theprocess.

In order to prevent the accumulation of too great a quantity of liquorin the product produced, the valve 10 is opened and the operation of thepump 11 is regulated through the medium of the valve 10 to withdrawliquor from the magazine and return it to the tank 3 where it may bereheated to the required point by the admission of steam to thetankthrough the valved pipe 4. By withdrawing the excess liquor in thismanner and returnin it directly for reuse, its heat and containeextractive properties are conserved.

Moreover, it will be noted that the remaining liquor containing solventextractives in the magazine at the grinding zone acts on the fibers asthey are separated at the stone and so affects the encrusting materialsof the wood, as to produce from the treated product a whiter and moredesirable pulp.

In practical grinding, it has been found that bundles of fiberfrequently appear in the product and these have a bad effect when thepulp is run into paper. I have been able to overcome this objectionablefeature because of the prior softening eflect of the liquor when chargedwith the extractives, with the result that the fibers readily se arateone from the other under the grinding action.

An important characteristic of the improved process is that the wood issubjected to the action of the charged liquor in advance of the grindingzone, so that the function of the solvents in the liquor is of graduallyincreasing effect toward the grind ng zone, with its maximum effect at"the point where the fibers are separated--that is at the grinding'zone.Thus the li uor, 1nc1 dent to its being charged with tie extractives ofthe wood being treated is of gradually-increasing strength toward theinding zone, and hence its maximum e ect is had at that point where thewood is most susceptible to the treatment, that is where i the fibersare separated one from the other. Thus the product is given the maximumtreatment in gradually-increasing steps from the initial spraying to thegrinding point, thus insuring the most effective separation andtreatment of the fibers.

It will be apparent that I may use in my process any desired characterof liquor which will have the required effect on the wood in themagazine.

What I claim is:

1. In combination with a grinder, a liquor supply tank, means fordistributing liquor in the upper portion of the magazine, and means forwithdrawing liquor from the lower portion of the grinder and dischargingit into said tank.

2. In combination with a pulp grinder, means for removing excess liquorfrom the grinder before said liquor reaches the point at which the pulpis discharged from said grinder.

3. Apparatus as defined in claim 2 having means for returning the midwithdrawn liquor to the grinder for reuse.

4. Apparatus as defined in claim 2 having means for returning saidwithdrawn liquor to the grinder for reuse, and means for heating saidliquor during circulation.

5. A process of making ground wood pulp in a magazine grinder, the stepwhich consists in subjecting the wood in said grinder to the action ofwater and steam to heat and soften the Wood and withdrawing excess waterbefore it becomes mixed with the pulp in the grinder it.

6. In a process 0 making ground wood pulp in a grinder, the step whichconsists in withdrawing from the lower portion of the grinder excesswater, applied to the wood for the purpose of softening it before saidwater becomes mixed with the pulp in the grinder pit.

7. A process of making ground wood pulp, consisting in spraying the woodbefore and during the grinding period with preheated water charged withextractives from wood to soften and impregnate the wood with moistureand extractives to thereby prepare the wood for grinding and at the sametime release contained extractives, the released extractives beingintermixed with the water to enrich the same, withdrawing a substantialproportion of the excess water charged with extractives above the actualgrinding point, and recharging the grinder with the withdrawn watercharged with extractives.

8. The herein-described process of making ground wood pulp, consistingin subjecting the wood in the grinder to a spray of heated .water moreor less charged with the wood extractives, to thereby soften the woodand directly affect and release the contained extractives, and finallywithdraw undesirable excess of water charged with the wood extractivessubstantially at the grinding zone to prevent excess water in the groundpul the withdrawn charged water being redeiivered to the wood above thegrinding zone.

9. The herein-described process of making ground wood pulp, consistingin spraying water charged with extractives of the wood onto the woodabove the grinding zone to thereby prepare the wood for grinding throughsoftening the same and liberating undesirable constituents, collectingthe excess water with liberated constituents at the grinding zone,withdrawin such excess charged water from the grinding zone to preventsuper-saturation of the ground pulp, and utilizing such withdrawn waterfor recharging the wood above the grinding zone.

10. The herein-described process of making ground wood pulp, consistingin subjecting the wood in the grinderto the action of heated watercharged with extractives of wood to thereby soften and liberateextractives from the wood before the wme reaches the grinding zone,maintaining a desired saturation of the wood at the grinding zone bywithdrawing excess water with its charged extractives at the grindingzone,

and utilizing such excess charged water for initial wood treatment inthe grinder.

11. The herein-described method of making ground wood pulp, consistingin initially subjecting the wood remote from the grinding zone to spraysof heated liquor charged with wood extractives with the effeet to softenthe wood and increasingly charge the liquor with the wood extractives,subjecting the wood as in fiber form at the grinding zone to the liquorwith a maximum charge of extractives, and finally withdrawinlg allcharged liquor at the grinding zone ot er than that necessary to theproper pulp consistency. I

12. The herein-described method of making ground wood pulp consisting ininitially subjecting the wood in the grinder to sprays of liquor char edwith the extractives of the wood, t e spraying action being remote fromthe grinding zone to thereby soften the wood and increasingly enrich thetreating liquor with the removed oxtractives, and finally subjecting thewood at the grinding zone to the liquor at its maximum charge ofextractives to thereby directly affect the fibers of the wood as theyare liberated by grinding.

13. In a process of mechanically making wood pulp, that step whichconsists in dissolving t ose encrustin materials of the wood which arenot soluble in water by subjecting the wood prior to and while beingmechanically acted on to water intermingled with extractives of wood tothereby dissolve the said encrusting materials.

14.In a process of mechanically making wood pulp, that step whichconsists in dissolving those encrusting materials of the wood whicharenot soluble in water by subjecting the wood "means mechanically actedon to heated water intermingled with extractives of wood to therebydissolve the said encrusting materials.

15. A process of making wood pulp in a grinder which consists 'inspraying super heated water charged with solvent wood extractives ontothe wood in the grinder prior to the grinding action, subjecting thischarged water to the further heat of the friction incident to thegrinding action on the wood, withdrawing a substantial portion of suchcharged and heated water from the lower portion of the grinder, andcirculating such withdrawn charged water to the initial spray.

In testimon whereof I afiix my si nature.

F EDERICK K. FIS JR.

iii to and while being a

